Add nosv.can_breakdown attribute check

The nosv.can_breakdown attribute states if enough events for the
breakdown model of nOS-V are enabled at runtime. It is used to ensure
that breakdown traces have the progress events enabled along with others
required for proper visualization of traces.

The emulator will panic when the level is not enough, instead of relying
on users to always remember to enable the correct level.

CHANGELOG.md

@@ -9,7 +9,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
-- nOS-V model version increased to 2.2.0.
+- nOS-V model version increased to 2.3.0.
+- Prevent accidental use of nOS-V traces without required events for the
+  breakdown model using the `nosv.can_breakdown` attribute.
 
 ### Added
 

doc/user/emulation/events.md

@@ -1,7 +1,7 @@
 # Emulator events
 
 This is a exhaustive list of the events recognized by the emulator.
-Built on Jun 12 2024.
+Built on Jun 13 2024.
 
 ## Model nanos6
 
@@ -615,7 +615,7 @@ List of events for the model *tampi* with identifier **`T`** at version `1.0.0`:
 
 ## Model nosv
 
-List of events for the model *nosv* with identifier **`V`** at version `2.2.0`:
+List of events for the model *nosv* with identifier **`V`** at version `2.3.0`:
 <dl>
 <dt><a id="VTc" href="#VTc"><pre>VTc(u32 taskid, u32 typeid)</pre></a></dt>
 <dd>creates task %{taskid} with type %{typeid}</dd>

doc/user/emulation/versions.md

@@ -39,6 +39,8 @@ Track changes in emulator model versions.
 
 ## nOS-V
 
+- nosv 2.3.0
+    - Add `nosv.can_breakdown` attribute to metadata for breakdown checks.
 - nosv 2.2.0
     - Add support for progress events `VP{pra}`.
 - nosv 2.1.0

flake.nix

@@ -15,7 +15,7 @@
       nosv = prev.nosv.override {
         useGit = true;
         gitBranch = "master";
-        gitCommit = "af186f448d3b5675c107747f5c9237e7f4d31e4b";
+        gitCommit = "c668e3bbfae34cd9b8797811b29ae35361b267ca";
       };
       nanos6 = prev.nanos6.override {
         useGit = true;
@@ -37,7 +37,8 @@
       ovniFixed = prev.ovni.override {
         useGit = true;
         gitBranch = "master";
-        gitCommit = "68fc8b0eba299c3a7fa3833ace2c94933a26749e";
+        # Includes ovni_attr_* API
+        gitCommit = "d1e8a62396ae92934c0b6e248d5f6ff921bef56f";
       };
       # Build with the current source
       ovniLocal = prev.ovni.overrideAttrs (old: rec {

src/emu/nosv/breakdown.c

@@ -23,6 +23,7 @@
 #include "recorder.h"
 #include "sort.h"
 #include "system.h"
+#include "thread.h"
 #include "task.h"
 #include "track.h"
 #include "value.h"
@@ -48,6 +49,28 @@ create_cpu(struct bay *bay, struct nosv_breakdown_cpu *bcpu, int64_t gindex)
 	return 0;
 }
 
+static int
+check_thread_metadata(struct thread *th)
+{
+	if (th->meta == NULL) {
+		err("thread has no metadata");
+		return -1;
+	}
+
+	JSON_Value *val = json_object_dotget_value(th->meta, "nosv.can_breakdown");
+	if (val == NULL) {
+		err("missing nosv.can_breakdown attribute");
+		return -1;
+	}
+
+	if (!json_value_get_boolean(val)) {
+		err("nosv.can_breakdown is false, missing events to enable breakdown");
+		return -1;
+	}
+
+	return 0;
+}
+
 int
 model_nosv_breakdown_create(struct emu *emu)
 {
@@ -88,6 +111,13 @@ model_nosv_breakdown_create(struct emu *emu)
 		}
 	}
 
+	for (struct thread *th = emu->system.threads; th; th = th->gnext) {
+		if (check_thread_metadata(th) != 0) {
+			err("bad nosv metadata in thread: %s", th->id);
+			return -1;
+		}
+	}
+
 	return 0;
 }
 

src/emu/nosv/setup.c

@@ -82,7 +82,7 @@ static struct ev_decl model_evlist[] = {
 
 struct model_spec model_nosv = {
 	.name    = model_name,
-	.version = "2.2.0",
+	.version = "2.3.0",
 	.evlist  = model_evlist,
 	.model   = model_id,
 	.create  = model_nosv_create,

test/emu/nosv/instr_nosv.h

@@ -12,6 +12,7 @@ static inline void
 instr_nosv_init(void)
 {
 	instr_require("nosv");
+	ovni_attr_set_boolean("nosv.can_breakdown", 1);
 }
 
 static inline uint32_t

test/rt/nodes/CMakeLists.txt

@@ -64,8 +64,11 @@ nodes_rt_test(../nanos6/several-tasks.c NAME several-tasks-level-3 LEVEL 3 SORT)
 nodes_rt_test(../nanos6/several-tasks.c NAME several-tasks-level-4 LEVEL 4 SORT)
 
 # Same but with breakdown enabled
-nodes_rt_test(../nanos6/several-tasks.c NAME several-tasks-breakdown-level-1 LEVEL 1 SORT BREAKDOWN)
+nodes_rt_test(../nanos6/several-tasks.c NAME several-tasks-breakdown-level-1 LEVEL 1 SORT BREAKDOWN
-nodes_rt_test(../nanos6/several-tasks.c NAME several-tasks-breakdown-level-2 LEVEL 2 SORT BREAKDOWN)
+  SHOULD_FAIL REGEX "nosv.can_breakdown is false, missing events to enable breakdown")
+nodes_rt_test(../nanos6/several-tasks.c NAME several-tasks-breakdown-level-2 LEVEL 2 SORT BREAKDOWN
+  SHOULD_FAIL REGEX "nosv.can_breakdown is false, missing events to enable breakdown")
+# From level 3 up the breakdown can be enabled
 nodes_rt_test(../nanos6/several-tasks.c NAME several-tasks-breakdown-level-3 LEVEL 3 SORT BREAKDOWN)
 nodes_rt_test(../nanos6/several-tasks.c NAME several-tasks-breakdown-level-4 LEVEL 4 SORT BREAKDOWN)
 

test/rt/nosv/CMakeLists.txt

@@ -53,8 +53,12 @@ nosv_test(several-tasks.c SORT NAME several-tasks-level-3 LEVEL 3)
 nosv_test(several-tasks.c SORT NAME several-tasks-level-4 LEVEL 4)
 
 # Same but with breakdown enabled
-nosv_test(several-tasks.c SORT NAME several-tasks-breakdown-level-0 LEVEL 0 BREAKDOWN)
+nosv_test(several-tasks.c SORT NAME several-tasks-breakdown-level-0 LEVEL 0 BREAKDOWN
-nosv_test(several-tasks.c SORT NAME several-tasks-breakdown-level-1 LEVEL 1 BREAKDOWN)
+  SHOULD_FAIL REGEX "nosv.can_breakdown is false, missing events to enable breakdown")
-nosv_test(several-tasks.c SORT NAME several-tasks-breakdown-level-2 LEVEL 2 BREAKDOWN)
+nosv_test(several-tasks.c SORT NAME several-tasks-breakdown-level-1 LEVEL 1 BREAKDOWN
+  SHOULD_FAIL REGEX "nosv.can_breakdown is false, missing events to enable breakdown")
+nosv_test(several-tasks.c SORT NAME several-tasks-breakdown-level-2 LEVEL 2 BREAKDOWN
+  SHOULD_FAIL REGEX "nosv.can_breakdown is false, missing events to enable breakdown")
+# From level 3 up the breakdown can be enabled
 nosv_test(several-tasks.c SORT NAME several-tasks-breakdown-level-3 LEVEL 3 BREAKDOWN)
 nosv_test(several-tasks.c SORT NAME several-tasks-breakdown-level-4 LEVEL 4 BREAKDOWN)